Mendoza is a 22-year-old forward who represented Colombia at the 2009 U-17 World Cup in Nigeria and the 2011 U-20 South American championship in Peru. He also represented Colombian club Deportivo Cali.
"We are delighted to add Mendoza to our squad which is looking well-balanced now. The team has been gelling well for the last couple of weeks with plenty of hard work put in by the players and support staff.
"We look forward to be in Chennai soon and have an exciting season ahead in the Hero Indian Super League," said Chennaiyin FC co-owner Vita Dani.
Chennaiyin's squad comprises 16 domestic players and 12 foreigners, including player-manager Marco Materazzi, marquee foreigner Elano and former Manchester United defender Mikael Silvestre.
Chennaiyin FC played a practice game against Army XI Wednesday at the Bangalore Football Stadium and won 7-1 with Eduardo Silva and Bernard Mendy scoring two apiece while Abhishek Das, Cristian Hidalgo and Jaison Vales netted a goal each.
Chennaiyin FC start their Hero Indian Super League campaign with an away fixture against FC Goa Oct 15 while their first home assignment is against Kerala Blasters Oct 21.
Goalkeepers: Abhijit Mondal, Shilton Paul, Gennaro Bracigliano (France). Defenders: Gouramangi Singh, Dhanachandra Singh, Khelemba Meetei, Abhishek Das, Bernard Mendy (France), Jairo Suarez (Colombia), Marco Materazzi (Italy), Mikael Silvestre (France).
Midfielders: Harmanjot Singh Khabra, Denson Devadas, Dane Pereira, N.P. Pradeep, Jaison Vales, Anthony Barbosa, Sukhwinder Singh, Cristian Hidalgo (Spain), Bojan Djordjic (Sweden/Serbia), Bruno Pelissari (Brazil), Pierre Tillman (Sweden), Elano (Brazil).
Forwards: Jeje Lalpekhlua, Jayesh Rane, Balwant Singh, Eduardo Silva Lerma (Spain), John Stiven Mendoza (Colombia).